1. Field of the Invention.
This invention relates to instruments for determining human pulse rate and body temperature.
2. Prior Art.
Traditionally, pulse rate has been determined by feeling the pulsations of blood flowing at the wrist or other suitable spot on the body and counting their number for some predetermined time. This method is still almost universally used, although recently electronic pulse rate meters have made their appearance, primarily for use by joggers, etc. Such instruments, however, have not yet found acceptance in a hospital environment. The probable reasons for this are discussed below.
Electronic thermometers, on the other hand have found wide acceptance in hospitals. At this time, well over 50% of the temperature measurements made in hospitals are made by electronic thermometers. A clinical electronic thermometer typically uses a thermistor sensor and a disposable sheath to prevent cross infection. It takes some 30 to 45 seconds to make a body temperature measurement using electronic thermometers currently available.
It has been felt that since a nurse must be in attendance with a patient for 30 to 45 seconds anyhow, she might as well count the patient's pulse. An electronic pulse rate meter would be just one more item for the nurse to carry and would not save any time. Consequently, there has been no incentive for hospitals to invest in electronic pulse rate meters.
In a copending patent application Ser. No. 424,601, filed contemporaneously herewith, I have described an electronic thermometer suitable for clinical use with which it is practical to make temperature measurments in just a few seconds. If it is only necessary for the nurse to attend the patient for a few seconds, it will become desirable for hospitals to use electronic pulse rate meters, if same can be made convenient and economical.
It is thus an object of the present invention to provide a combined thermometer and pulse rate meter using a single transducer to sense both temperature and pulse rate.
It is a further object of the present invention to provide a novel means of measuring pulse rate.